The third -- and promised final -- installment in the booze-fueled exploits of the so-called Wolf Pack is bombing at the Memorial Day weekend box office, where it is being run over not only by “Fast & Furious 6” but also by the 3-D animated family film “Epic.”

When “The Hangover Part III” debuted late Wednesday, industry prognosticators were estimating that the sequel would gross about $80 million in its first five full days of release -- a steep drop from the $135 million the second movie made between Thursday and Monday in 2011, but a decent enough opening in absolute terms.

But early returns Friday suggested that the Warner Bros. “Hangover” film, which cost $103 million and was trashed by critics, could gross as little as $48 million in its five-day debut. The best-case estimates only have “The Hangover Part III” grossing about $55 million, well below the $80-million projection.

The new “Fast” film, on the other hand, is racing away from the competition. Industry estimates before the Universal movie debuted late Thursday showed that “Fast & Furious 6” could gross as much as $100 million in its first four full days in theaters. The $160-million sequel should hit that mark, early returns showed.

Meanwhile, 20th Century Fox’s “Epic” is performing at the top end of, and even beyond, industry estimates. The $100-million-plus family film is expected to gross as much as $50 million in its first four days in theaters. “The Hangover Part III” over those same four days is projected to sell about $40 million in tickets.

Though the second “Hangover” movie grossed $586.8 million worldwide, the film was not received nearly as well as the 2009 original, which became a surprise word-of-mouth phenomenon. The new sequel reunites Bradley Cooper, Ed Helms and Zach Galifianakis in Las Vegas, where the franchise was launched.

Only 38% of the film’s reviews were positive, according to Moviereviewintelligence.com. According to the review aggregation site, the first two “Hangover” films had reviews that respectively were 71% and 46% positive.